Device for dressing grinding wheels



June 6, 1933. w. SHOTEY DEVICE FOR DRESSING GRINDING WHEELS Filed March 14, 1932 I INVENTOR ATTO RN EYs Patented June 6,1933 1,912,410

UNITED STATES PATENT OFFICE WILLIAM SHOTEY, OF DETROIT, MICHIGAN DEVICE FOR. DRESSING GRINDING WHEELS Application filed March 14, 1932. Serial No. 598,631.

. The present invention pertains to a novel Reference to these views will now be made device for dressing the edges of a grinding by use of like characters which are employed wheel so that the latter may be inserted to designate corresponding parts throughinto the spaces between the teeth of a roughly out.

shaped broach for internal gears or between In Figures 1, 2 and 3 is illustrated a suit- 55 the teeth of spur gear and accurately form able base member 1 carrying a stub shaft 2 the involute outlines of the teeth. Accordon which are mounted a pair of congruent ingly, it is necessary to form concave involute spaced disks 3 of equal circumferences. A surfaces on the grinding wheels in order that pin 4 is preferably passed through both disks these surfaces may form corresponding conand into the base member to prevent turning 00 vex involute surfaces. of the disks.

The invention embodies a fixed circular 'On the shaft 2 and between the disks 3 is disk or arcuate member having a radius of pivotally mounted an arm 5 having in its curvature equal to the radius of the base upper end a slot 6 extending beyond the circircle of the gear to be ground. Upon this cumference of the largest disks which the as member is mounted a frame lying tangential device will accommodate, as will presently thereto and adapted to be turned on the appear. Roller bearings 7 are mounted on member while maintaining its tangency. 1 A a stud 8 which lies loosely in the opening, given point on this frame therefore describes and these bearings lie directly over the the involute curve of the base circle. The disks 3.

frame in fact is utilized as the holder for a A hollow rectangular frame 9'lies between a tool which referably has its point lying in the disks 3 and bearings 7 and has its sides the plane oftangency, so that this point also resting upon the disks and engaged by the describes the involute curve. When the bearings. A screw 10 adjustable in the upgrinding wheel is brought against the point per end of the arm 5 bears u on the stud 8 rs and the frame turned about the arcuate memand is ada ted to clamp t e bearings 7 her, the point cuts the involute curve into against the rame 9 for a purpose which will the grinding wheel. presently appear.

The invention also embodies means for Aboss 11 extends laterall from'the frame shifting the tool point from one position to 9, and on the boss is rotatab y mounted a cap so another, these positions being such that in- 12 having a finger 13 extending therefrom at volute surfaces are cut on both faces of the right angles to the disks 3. A dressing tool wheel, thus enablin the wheel to grind both 14 is mounted transversely in the finger 13 sides of an"interental space at the same and is adapted to be adjusted len hwlse by time. a locknut 15. A key 16 is secure diametri- .85

The invention is fully disclosed by way of cally within the cap 12, as shown in Figure 4, example in the following description and in and enters a diametrical slot 17 in the outer the accompanying drawing, in whichend of the boss 9. A disk 18 is seated in the Figure 1 is a side elevation of the device; other end of the boss, and a rin 19 joins Fig. 2 is an end view, partly in section; the disk to the key 16, WhQI ORJJ' t e cap is 00 Fig. 3 is a plan view; gieldably held in 'a fixed posltion on the Fig. 4 is a section on the line 4-4 of Fig- 0s 11. are 1; The grinding wheel 20 to be dressed by Fig. 5 is a diagram illustrating the inthe tool 14 is designed to enter the inter-denvolute movement of the dressing tool point; tal spaces of a broach for internal gears to 06 Fig. 6 is a diagrammatic view showing the accurately finish the tool. Oonsequentl it operation of. the grinding wheel. on'an mvois desired that the opposite faces of thew eel lutebroach for internal gears; and 20 be shaped at their edges in concave in- Fig. 7 is a similar diagram showing the volute fas ion, as indicated by the numeral operation of the wheel on a spur gear. 21, in order to grind the convex involute faces. In being dressed the wheel is driven from a spindle on which it is mounted.

In order to enable accurate initial setting of the frame 9, a locating or centering tool is adjust-ably mounted in a vertical slot 22 formed in the base member 1. This device comprises a casing 23 guided in the slot and containing a spring pressed pin 24 adapted to enter a correspondingly shaped openin in the side of the frame as illustrat in Figures 2 and 3. The casing 23 cannot slip in any direction in the horizontal plane because of its mounting in the base member 1 and maintains its elevation after the pin 24 is inserted in the frame, whereby the frame and the tool are maintained in a fixed posi t1on while the bearing 7 is being clamped upon the frame. The pin is then withdrawli from its openin and held in the withdrawn position by a nger 26 fixed thereto and ggapted to engage the end wall of the casing In the operation-of the device, the wheel 20 or the base 1 is so adjusted that the periphery of the wheel 20 passes through the plane of tangency of the frame 9 to the disks 3. The point of the tool 14 lies in the same plane and therefore describes an involute curve with reference to the disks 3 when the frame 9 is turned on the disks without slippage. The frame 9 is turned b swinging the arm 5 which may be graspe at its upper end. The contacting surfaces of the frame 9 and disks 3 may be roughened in order to avoid slippage, and if the bearings 7 are clamped tightly upon the frame by means of the screw 10, they will turn before the frame slips on the disks 3.

It will be seen in Figures 1 and 3 that the point of the tool 14 lies at one side of a plane which is normal to the plane of tangenc of the plane 9 to the disks 3. This normal p ane is midway between the curved edges 21 and represents a plane which bisects an interdental s ace radially. One edge 21 is dressed,

b slow y swinging the arm 5 to the same side 0 the normal plane while the wheel 20 is being rotated.

In order to set the tool for dressing, the pther edge 21, the pin 24 is first returned to its 0 ning 25 and the cap 12 is pulled outwa y against the spring 19 until the key 16 is out of the slot 17 The cap is then turned throu an angle of 180, and the key is reinserted 1n the slot. This turning of the cap swin the tool around to the other side 'of the w eel 20 and in such a manner that both the old and new positions of the tool point are symmetrical with respect to the normal plane. The pin 2* is now withdrawn and the remaining edgp 21 is dressed by swinging the arm to t e same side of the normal plane in the manner already described.

The circumference of the disks 3 represents the base circle of the broach or gear to be ground. The tool point, in moving on this circle in the manner described, therefore describes the involute curve of the circle. For another size of broach or gear, the disks 3 are replaced by another pair of disks having the circumference of the base circle of that broach or gear.

In Figure 5 the operation of the tool is illustrated diagrammatically to show the involute movement of its point as the frame 9 moves from its initial position A to another position B while held tangential to the disks 3 and without slipping relatively thereto. It will be understood also that the disks 3 need not be complete circles but require an arouate edge only where contacted by the frame 9 in the movement of the latter.

Figure 6 illustrates the dressed wheel in the operation of finishing the involute faces of a stub tooth involute broach for forming internal gears. The periphery 31 of the wheel extends substantially to the base circle as indicated. Figure 7 shows the wheel employed in finishingthe teeth of a spur gear 32, and in this case the periphery of the wheel extends slightly beyond the base circle.-

In the use of the tool for either a broached or a spur gear, the periphery 31 1s regulred to cut an arc of a circle. The periphery therefore requires a transverse concavity having the radius of the arc to be cut, and this formation may be imparted by a su table dressing means of any type known in the art.

Although a specific embodiment of the invention has been illustrated and described, itwill be understood that various alterations in the details of construction may be made without departing from the scope of the invention, as indicated by the appended claims.

What I claim is 1. A device for dressing grinding wheels comprising a base, an arcuate member carried thereby, a rigid arm pivoted to said base at the center of said arcuate member, a clamping member adjust-ably mounted in said arm, a tool holder clamped tangentially upon the periphery of said arcuate member by said clamping member, and a dressing tool carried by said holder, said tool holder having its working point disposed in the plane of tangency' of. said holder to said arcuate member.

2. A device for dressing grinding wheels comprising a base, an arcuate member carried thereby, a rigid arm pivoted to said base at the center of said arcuate member, a clamping member adjustably mounted in arm, a tool holder clamped tangentially upon the periphery of said arcuate member by said clamping member, and a dressing tool carried by said holder, said tool holder having its working point disposed in the plane of tangency of said holder to said arcuate member, said point being disposed at one side of a plane normal to said plane of tangency, said point being adjustable from one to the other of two positions symmetrical with respect to said normal plane.

3. A device for dressing grinding wheels comprising a base, an arcuate member movably carried thereby, a rigid clamping member pivoted to said base at the center of said arcuate member, a tool holder clamped tangentially upon the periphery of said arcuate member by said clamping member, and a dressing tool carried by said holder, said tool being ofl'set axially from said arcuate member.

4. A device for dressing grinding wheels comprising a base, an arcuate member carried thereby, a clamping member pivoted to said base at the center of said arcuate member, a tool holder clamped tangentially upon the periphery of said arcuate member by said clamping member, a dressing tool carried by said holder, and a centering pin engageable with said tool holder for locating the same during adjustment of said clamping member.

In testimony whereof I afiix my signature.

WILLIAM SHOTEY. 

